Users Guide: Network Microcontroller Supplement User Manual

High-Speed Microcontroller User’s
Guide: Network Microcontroller
Supplement
196
SOCKET FUNCTIONS/POINTERS
PARAMBUFFER
The DS80C400 silicon software exports a pointer the six-argument parameter buffer (PARAMBUFFER) that is used by the DHCP task for
its socket-function calls. The user application is free to use this parameter buffer but should recognize that if more than one task needs to
use a parameter buffer, separate buffers must be declared for each task, or the PARAMBUFFER must be protected from concurrent access.
socket
Description: int socket(
int domain, /* currently ignored */
int type, /* type of socket (UDP = 00h or TCP = 01h) */
int protocol); /* currently ignored */
The socket function creates a network socket (a local endpoint) for TCP or UDP communication. The type can either be
SOCK_STREAM for TCP sockets or SOCK_DGRAM for UDP sockets. The domain and protocol parameters are ignored. The
socket function returns a socket handle (i.e., an identifier for the new socket), but has no specific local address assigned to
it. T
o use it as a server socket, the use of bind is required. To use a streaming (TCP) socket, the socket must be connected
using either connect or listen/accept. To destroy/free a socket, use closesocket. This is the only function that returns a sock-
et number. All other socket functions require the socket number to be passed to them to access the correct socket. Note: The
socket function calls gettaskID through the function r
edirect table to get the current task ID.
closesocket
Description: int closesocket(
int s); /* closes socket with handle = s */
The closesocket function closes a socket. It closes the socket having handle, which was cr
eated by the socket call and
returns a success/failure code in the accumulator.
sendto
Description: int sendto(
int s, /* send to socket with handle s */
void *buf, /* datagram data array at *buf */
int len, /*
size of datagram to be sent */
int flags, /* currently ignored */
struct sockaddr *addr, /* target address */
int addrlen); /* size of address structur
e */
The sendto function sends a UDP datagram to the specified address. The target address is specified at *addr; addrlen is the
size of the sockaddr structure. The datagram itself is referenced by *buf, and len is the size of the datagram. The flags para-
meter is ignored. The sendto function is unable to detect whether the datagram has successfully r
eached the destination and
only returns a failure code on local errors. Use bind to specify a local port number. Without bind, sendto chooses a random
local port.
INPUT PARAMETER#–DESCRIPTION OUTPUT DESCRIPTION
s
*buf
len
flags
*addr
addrlen
Param0[0]–socket handle #
Param1[0:2]–pointer to UDP data
Param2[0:1]–size of datagram
Param3–currently ignored
Param4[0:2]–pointer to target addr
Param5[0]–size of addr structure
ACC Return value (= 0 for success)
INPUT PARAMETER#–DESCRIPTION OUTPUT DESCRIPTION
s Param0[0]–socket handle # ACC
Return value (= 0 for success)
INPUT PARAMETER#–DESCRIPTION OUTPUT DESCRIPTION
domain
type
protocol
Param0–currently ignored
Param1[0]–00h = UDP
01h = TCP
Param2–currently ignored
ACC
R0
Return value (= 0 for success)
Socket handle
Maxim Integrated